Agreements between Mussolini’s government and Pius XI to regularize relations between the Vatican and the Italian government, strained since 1870 when the Papal States had been incorporated into a united Italy. By a treaty (Concordat) and financial convention the Vatican City was recognized as a fully independent state under papal sovereignty. The concordat recognized Roman Catholicism as the sole religion of the state. The Vatican received in cash and securities a large sum in settlement of claims against the state.